splitdb.py is a utility program that takes as input a .db or .db.gz file and splits it into many smaller .db.gz files respecting the hierarchy boundaries. output files are ready for DOCK_3.6 input.
splitdb.py input.db[.gz] outputPrefix NumFamiliesInOutput
The file is in your dockenv/scripts or $DOCK_BASE/scripts/
A version is also kept is ~/Source/bks_src/splitdb.py